1. Field of Invention
The present invention relates to a method of producing dehydrated foodstuffs capable of quick or rapid reconstitution. More particularly, the present invention is directed to a process for processing vegetable material which includes steps of cooking, freezing, thawing, and dehydration carried out under controlled conditions wherein the vegetable material is subjected to a sequence of freezing and thawing at least twice. The present invention is also directed to a process for producing dehydrated vegetables capable of quick or rapid reconstitution or rehydrating by a process which involves subjecting foodstuff, such as vegetable material, i.e., potatoes, to freezing followed by thawing and then at least one additional sequence of freezing and thawing prior to drying.
2. Description of the Prior Art
Dehydration is one of the oldest methods for preserving food. Commercial production of dehydrated foods, however, is a development of the twentieth century. During the last fifty years, many procedures have been developed in an attempt to produce dehydrated products which upon reconstitution resemble fresh foods in taste, texture, and appearance. More recently there has been a general concern for rehydrating large piece products. Most of these efforts have resulted in unsatisfactory processes and products. A problem common to prior dehydration methods is a phenomenon referred to as case-hardening or the formation of a horny, vitreous material primarily on the surface of the foods. It has been postulated that this may result from the collapse of the cellular structure of the vegetable which dehydrates into a dense mass of material of low rehydration characteristics.
U.S. Pat. No. 4,889,734, commonly owned with the present invention, is an example of more recent efforts to produce quick-reconstituting foodstuffs wherein the foodstuff is frozen prior to being dehydrated.
U.S. Pat. No. 2,278,472 discloses advantages of freezing food prior to dehydration.
U.S. Pat. No. 2,707,684 discloses that if potato pieces are rapidly frozen prior to dehydration, the final products will have a slow rehydration rate.
U.S. Pat. No. 2,713,003 preconditions food products by freezing, throughout or superficially, prior to dehydrating.
U.S. Pat. No. 2,729,566 discloses a process which involves rapid freezing followed by a slow thawing.
U.S. Pat. No. 3,188,750 attempts to produce a dehydrated product possessing a high degree of biological integrity by first hot air drying raw material prior to freeze drying which is preferably followed by another hot air drying.
U.S. Pat. No. 3,359,123 is directed to rendering potatoes more amenable to freeze-thaw procedures by a controlled cooking procedure followed by dehydrating the product.
U.S. Pat. No. 3,573,070 discloses a process which comprises freezing prior to combined freeze drying-hot air drying in an attempt to produce improved dehydrated products.
U.S. Pat. No. 3,644,129 is based on the discovery that combined freeze drying-hot air drying is effective in improving the rehydration characteristics of the dehydrated product.
The foregoing disclosures are examples of attempts made to overcome shortcomings of dehydrated food products as compared to freshly prepared foodstuff. The food industry has had to rely on similar procedures to prepare dehydrated vegetable over the years. Cooking and eating habits have been influenced by a number of factors which reduce the time allocated for food preparation in households as well as in eating establishments. This has caused a need for good nutritious foods which can be prepared quickly and easily. Notwithstanding, numerous efforts to develop industrially produced and commercially acceptable dehydrated food products, there is a limited number of dehydrated vegetable products on the market. Such vegetables are primarily used as flavoring in soups, stocks, casseroles, and the like. Moreover, dehydrated vegetables used in instant soups, i.e., having a reconstitution time of less than about 10 minutes, have been small in size in order to permit preparation within the prescribed time period. Normally the vegetable piece size is no larger than about 1/8 inch in cross section. Typically, the dehydrated products have been reduced to a powder. Complaints about such products include that the dehydrated pieces reconstitute incompletely and are tough and chewy despite their small size. Larger vegetable pieces have only recently been used as ingredients in commercial mixes containing dehydrated vegetables, stock seasoning, and noodles. These mixes are used as starting materials for preparation of soup to which only water and meat need be added in the kitchen. Their recipe normally requires as long as 1/2 to 11/2 hours in preparation for consumption.
Those concerned with these and other problems recognize the need for an improved dehydrated foodstuff capable of quick or rapid reconstitution or rehydration.